TU/ecomotive chooses the AE120 in the modular EV ARIA
TU/ecomotive’s vision for the future of mobility goes beyond electric driving; it revolves around a fundamental focus on sustainability. Their latest vehicle, the ARIA, is a modular electric city car specifically designed for repairability. By making components easy to replace—from individual battery packs to body panels—the team aims to keep cars on the road longer and drastically reduce their lifetime carbon footprint.
A drivetrain built on sustainability
A car that’s meant to last decades naturally demands a drivetrain built around a philosophy of precision and durability. To achieve this, the student team at Eindhoven University of Technology developed a dual-motor rear-wheel drive system that combines efficiency with the torque required for urban driving.
Apex Dynamics was happy to contribute. By supplying two high-precision inline gearboxes and actively supporting the design of a custom adapter, Apex Dynamics helped the team bridge the gap between the electric motors and the road surface. This allows the ARIA to drive as efficiently as it can be repaired. The configuration with two independent electric motors driving the rear wheels ensures superior handling and, of course, redundancy.
Efficiency
But pure engine power alone isn’t enough. Electric motors perform optimally at high RPM, while the wheels of a city car need torque to accelerate smoothly from a standstill. Without an efficient transmission, enormous, heavy motors would be required, increasing weight and limiting range. Moreover, this would hamper complex repairability—the core principle of ARIA. Furthermore, it would make self-repairing more difficult, undermining our sustainability goals.
“A transmission solution was needed to bridge this gap. The requirements were strict: a gearbox that could efficiently multiply the engine’s torque while also fitting into the tight mechanical space of our rear suspension. The solution had to be compact, lightweight, and simple, but above all, effective, in line with ARIA’s philosophy of repairability..”
The choice for the AE120 gearbox
To meet the team’s stringent requirements, the Apex Dynamics AE120-007 was implemented. A crucial advantage for the team was the wide range of gear ratios in our standard catalog. This allowed TU/ecomotive to perfectly tailor the system to their specific requirements without having to limit their own designs to a small selection of components.
“In the selection process, we sought the ideal balance between torque and speed. While sufficient pulling power was needed to climb steep hills from a standstill, top speed could not be limited too early by the maximum RPM of the engines. The 1:7 gear ratio offered the perfect compromise: it delivers the necessary power at low RPM for acceleration and climbing hills, while allowing the engines to spin freely enough for a practical top speed.”
The specifications of the selected AE120-007 are:
- Nominal output torque: 300 Nm
- Maximum output torque: 560 Nm, the same as a Lamborghini Huracán
- Maximum engine speed: 8,000 rpm, the same as a Porsche 911 GT3
Drivetrain overview
The final drivetrain is a paragon of both efficiency and clarity. Power flows in a logical, linear path: from the rear motor to the custom-made adapter, through the Apex AE120 torque multiplication gearbox, and finally via a second adapter to the driveshaft, which is connected to the wheel hub via a splined interface.
This clear modular separation -motor, gearbox, driveshaft, and wheel- not only minimizes mechanical play, but also directly supports ARIA’s accessibility mission. Because the drivetrain is divided into individual, recognizable components, it’s intuitive to understand and document, even for inexperienced users. This transparency simplifies the learning process, making disassembly easy, and repairs, should a component ever require maintenance, feel accessible rather than intimidating.
Partnership
Integrating industrial precision into an innovative student project often presents technical challenges. This project demonstrated the power of collaboration: Apex Dynamics not only supplied the hardware but also contributed to the engineering process.
Together with the students, a custom adapter plate was designed that provides a robust connection between the electric motors and the input of the AE120 gearbox. This integration guarantees the reliability of the drivetrain and ensures that the system remains accessible for maintenance, fully in line with the ARIA philosophy.
